The present invention relates primarily to containers, bottles, dispensers, canisters and the like and, more particularly, to an indicator mechanism to indicate the number of times the container, bottle, dispenser or canister has been opened or used. The invention can also be used for any other application in which the number of times a given activity is performed must be indicated.
In the medical field, medical drugs have a predetermined therapeutic range in which the effects of taking the drug are beneficial. Under-utilization of a drug may endanger the user with the drug's side effects without reaching levels necessary for a therapeutic action. On the other hand, over-utilization may cause side effects or toxicity to a much greater extent than any possible benefit. Thus it is critically important that a patient follow prescribed directions on medications, yet frequently patients forget whether they have taken medication and either omit doses or repeat them.
A considerable number of pill-timing schemes have been used to solve the problem of reminding a patient to take a dose of medicine or reminding the patient that the patient has already taken the dose. The most used ones involve some scheme of compartmentalization of the necessary medication, such that the pills are placed in compartments that are labeled by day, dose number or time of day, or that are serially numbered. These devices are reasonably satisfactory only if a responsible person is available and has the time and patience to fill the compartments properly.
Some medication is not in the form of a pill or capsule at all, but is instead an aerosol, such as asthma medication or other common respiratory tract medication. These medications are often packaged as a liquid in a pressurized canister which releases a measured aerosol dose into the patient's mouth or nose upon activation. Of course, such medications are not amenable to packaging in numbered compartments.
In dispensing pills of a single type, a number of window-containing bottle caps have been invented. Through the window a movable element marked with an index is visible. In only a few devices does the indicating element index in position relative to the window each time the cap is loosened, removed, replaced, and re-tightened. Thus, by looking at the index mark displayed through the window, a user can see where in repetitive sequence of dose he or she is. One limitation to most such devices is that they are designed to operate only with closures that disengage from a container by application of a rotative force, such as threaded or bayonet-type closures. The devices generally do not operate with closures that snap off from a container or other devices in which the container contents are accessed by the application of an axial force such as a push-actuated canister.
A serious disadvantage of prior art devices of the window indexing type is that there is no warning to the user in case the user does not turn the device far enough during the opening or closing to properly advance the window. Unless the user is alert to the index value before opening and then after closing such devices, the user will be unaware that the window failed to advance to a new index. Most users, especially the elderly who may not understand how the device operates, will not be this alert to the functioning of the device. In addition, most prior art devices fail to provide positive locking in both directions of movement; thus, the index may be moved appropriately when the device is opened or closed, but additional movement is not prevented when the device is moved in the opposite direction. This allows the index to drift, often causing failure or an incorrect reading, particularly after the device has been used over a period of time.
The device of U.S. Pat. No. 4,011,829 issued Mar. 15, 1977 to Wachsmann, et al., attempts to provide positive locking in both directions, but because of the direction of the tooth designed to prevent movement of the index upon closure, the device may not work reliably, particularly after wearing with use. Also, the device of Wachsmann does not provide space for the ratchet teeth to slide past the engagement teeth when the device is moving in a direction wherein such teeth should disengage, which may cause unreliable operation over a period of time. Another drawback of this device is its inclusion of a complicated "child proofing" feature with the indexing feature, which makes the device quite complex. Other features of this device, such as the method of providing the lost motion drive and the requirement of a post in the middle of the elements to hold the device together, also increase its complexity.
The device of U.S. Pat. No. 3,151,599 issued Oct. 6, 1964 to Livingston provides positive locking in both directions, but it does so by means of very closely spaced projections that would be difficult to manufacture economically. Furthermore, this device does not provide space for the projections to move while sliding past each other when not engaged.
The device of U.S. Pat. No. 4,666,051 issued May 19, 1987 to Trick has an indicator wheel with a serrated rim projecting above and below the plane of the wheel. The serrations engage mating serrations in upper and lower elements in order to drive the indicator mechanism. The serrations are rigid and, therefore, tend to wear excessively as they slide past one another.
The device of European Patent Application No. 87100917.2, published Jul. 27, 1987, by Schwab, has a cup-shaped exterior element that engages a frustoconical closure cap. The Schwab device is somewhat complicated in design and manufacture. The device of U.S. Pat. No. 4,220,247 issued Sep. 2, 1980 to Kramer also includes a cup-shaped exterior element which engages an inner element.
Other devices in the art include U.S. Pat. Nos. 4,511,050 by Nicol; 4,365,722 by Kramer; 4,749,093 by Trick; 4,782,966 by Thackrey; 4,753,189 by Mastman; 4,705,182 by Newel-Lewis; 4,662,520 by Griffen; 4,641,759 by Kelley; 4,634,012 by Kelley; 4,562,933 by Dennis; 4,528,933 by Allen; 4,511,050 by Nicol; 4,548,157 by Hevoyan; 4,501,370 by Kelley; 4,489,834 by Thackrey; 4,432,300 by Lyss; 4,419,016 by Zoltan; 4,405,045 by Villa-Real; 4,357,192 by Moser; 4,347,804 by Villa-Real; 4,094,408 by Ford; 3,996,879 by Walton; 3,960,713 by Carey; 3,926,326 by Grau; 3,921,568 by Fish; 3,887,099 by Gillman; 3,753,417 by Garby; 3,446,179 by Bender; 3,334,731 by Dale; 2,943,730 by Tregilgas; 2,939,597 by Greene; 2,587,147 by Guion; 498,851 by Adsit; 4,500,005 by Forrester; 3,151,599 by Livingston; 4,666,051 by Trick; 4,345,541 by Villa-Real; 4,440,306 by Van Buskirk; 2,767,680 by Lermer; 4,723,673 by Tartaglia; 2,644,452 by Brown; 4,646,936 by Frazier; 3,766,882 by Babbitt; 3,977,554 by Costa; 5,011,032 by Rollman; 5,188,251 by Kusz; 5,184,739 by Kusz; and European Patent 0 230 323 by Schwab.
It is thus apparent from a review of this art that there is a need for an improved indicator cap that operates by application of an axial rather than rotative force. Preferably, such a device should provide positive controlled movement of the index on both opening and closing of the device, while also providing an indication to the user that the index has functioned properly each time the device is used. The basic design of such a device can also be used in other applications where it is necessary to have a record of the number of times a given event occurs.
Preferably, such a cap should have a minimum of parts, should be easily manufactured and assembled using standard injection molding and assembly methods, and should be usable with ordinary containers that are not necessarily specially designed for the cap.